D5800_20 (18) 07-2018

Switch the instrument on a minimum of 30 minutes before running the test to allow temperature stabilization of measurement circuitry. Make sure that the glassware assembly and the vacuum pump are cleaned and all the connections are sealed. Thoroughly clean and dry all parts of the test cup and its accessories before starting the test. Check that the crucible and cover are free from lacquer. Stubborn lacquer should be removed by light abrasion with fine carborundum powder on a pad of cotton wool soaked in solvent or with a fibrous abrasive pad followed by a rinse with solvent. Pass the reamer through each of the three nozzles in the cover to ensure that they are clear. Warning, using a reamer with a diameter larger than 2 millimeters can enlarge the nozzles. This can lead to a wrong losses result due to increased airflow. Run the ball bearing through the extraction tube to ensure that it is clear of contaminants. Calibrate the vacuum measuring device in accordance with the manufacturer's instructions. Weigh the empty cup without its cover to the nearest 0.01 grams. Weigh into the tiered crucible, 65.0 grams, plus or minus 0.1 grams of reference fluid, to a precision of 0.01 grams. This mass is called m sub 1. Screw on the cover using the clamp and the spanner. During this phase, make sure that the specimen will never splash on the inside part of the cover. If this occurs even only one time, the test shall be repeated from 20.3 of the written standard. Connect the specimen temperature probe to the instrument. Press down on the locking lever located on the front of the heating block. Place the crucible in the heating block. Rotate the crucible, securing the flange under the screw heads. Adjust the final position of the extraction tube so that it is located in front of the arm of of the glass y piece and release the locking lever. Connect the extraction tube to of the glass y piece and secure the connection with the clamp. Be sure that the stainless extraction tube, the male connection, and the right arm of the y piece are properly aligned. Start the test by pressing the On key of the Central Processing Unit, CPU. In default configuration, the printer is activated. If not, refer to the instruction manual to activate the real-time printing of the specimen temperature and the vacuum curves. When the audible alarm signals the last three minutes of the test, stop the audible alarm by pressing on the Off key. Stay in front of the equipment and be prepared to disconnect the extraction tube. After 60 minutes, the test is automatically stopped and the end of the test alarm sounds. Remove the specimen temperature probe. Disconnect the extraction tube within 15 seconds, maximum. Press down the locking lever. Remove the crucible. Stop the audible alarm by pressing on the Off key. Stand the crucible in a cold water bath to a minimum depth of 30 millimeters. Check the printed report to ensure that the specimen temperature and vacuum-plotted curves stayed within the indicated limits. Occasionally, the electronics will generate erroneous noise spikes in the graph. These spikes are evident by a rapid temperature or pressure excursion followed by a rapid return to baseline conditions. These spikes are not cause for invalidating a test. If, however, there are gradual temperature and/or pressure drifts or excessive noise spikes beyond specific limits, perform the necessary system maintenance and/or calibrations. In addition, ensure the apparatus complies with the manufacturer's instruction and that the procedure has been adhered to. After these checks, rerun the test from 20.2 of the written standard. After 30 minutes, remove the crucible from the water bath. Dry the outside and carefully remove the lid. This phase is very critical. Make sure that the sample is never in contact with the inside part of the lid. It is very important, during the manipulation of the crucible, at the start and end of the test, to not splash the internal face of the cover with the specimen in the cup. When this occurs, it leads to higher losses, and the test must be rerun. Re-weigh the crucible without the lid to the nearest 0.01 grams. Calculate the m sub 2 mass by subtracting the empty cup mass from the mass measured in 20.8 of the written standard. Calculate to the nearest 0.1%, m over m, the evaporated loss of the reference fluid, using the following equation-- m sub 1 minus m sub 2, result divided by m sub 1, then multiplied by 100 where m sub 1 equals specimen mass before the test. And m sub 2 equals specimen mass after the test at 245.2 degrees Celsius. Compare the result obtained against the given value for the reference fluid. If the result is within limits, proceed to section 21 of the written standard. If the result is not within the limits, check that the apparatus complies with the manufacturer's instruction and that the procedure has been adhered to. Recheck the evaporation loss of the reference oil. To do so, proceed as described in 20.2 of the written standard.